Visiting Bangladesh scored 50 runs in 10.2 overs losing 2 wickets in the three-match ODI series opener at County Ground Chelmsford in England.
Najmul Hossain Shanto scored 13 runs off 23 balls while Shakib Al Hasan hit 19 runs from 19 balls.
Skipper Tamim Iqbal scored 14 runs off 14 balls before back to the pavilion and another opener Litton Das made a golden duck.
Earlier, Ireland captain Andrew Balbirnie won the toss and sent Bangladesh into bat first.
The series is particularly important for Ireland. Had they win the series 3-0, they'll pip South Africa and push them to the World Cup qualifiers. Bangladesh, however, want to keep the winning momentum going on ahead of the World Cup.
Bangladesh playing X1: Tamim Iqbal (C), Litton Das, Najmul Hossain Shanto, Mushfiqur Rahim (W), Shakib Al Hasan, Towhid Hridoy, Mehidy Hasan Miraz, Hasan Mahmud, Shoriful Islam, Taijul Islam, Ebadot Hossain.
Bd-pratidin English/Golam Rosul